KR20200024194A - Method and apparatus for adjusting uplink timing in a wireless communication system - Google Patents

Abstract

Provided are a method and a device for adjusting uplink timing in a wireless communication system. Specifically, a method of a terminal adjusting uplink timing in a wireless communication system includes: a step of transmitting, to a base station, an uplink signal; a step of receiving, from the base station, a timing advance (TA) command configured based on the uplink signal; and a step of performing uplink transmission to the base station by applying a timing advance (TA) commanded by the TA command. The TA command may be interpreted based on the subcarrier spacing of at least one frequency resource region to which the TA is to be applied.

Description

METHOD AND APPARATUS FOR ADJUSTING UPLINK TIMING IN A WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system, and more particularly, to a method for adjusting uplink timing and an apparatus supporting the same.

Mobile communication systems have been developed to provide voice services while ensuring user activity. However, the mobile communication system has expanded not only voice but also data service.As a result of the explosive increase in traffic, shortage of resources and users demand faster services, a more advanced mobile communication system is required. .

The requirements of the next generation of mobile communication systems will be able to accommodate the explosive data traffic, dramatically increase the transmission rate per user, greatly increase the number of connected devices, very low end-to-end latency, and high energy efficiency. It should be possible. For this purpose, Dual Connectivity, Massive Multiple Input Multiple Output (MIMO), In-band Full Duplex, Non-Orthogonal Multiple Access (NOMA), Super Various technologies such as wideband support and device networking have been studied.

The present specification proposes a method for adjusting uplink timing in a wireless communication system and an apparatus therefor.

In this regard, the present specification proposes a method for acquiring information on a Timing Advance (TA) and a Timing Advance Group (TAG) and an apparatus therefor. In addition, the present specification proposes a method for setting a TA command and an apparatus therefor.

Technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In a wireless communication system according to an embodiment of the present invention, a method of adjusting an uplink timing by a terminal, the method comprising: transmitting an uplink signal to a base station; Receiving a TA command (Timing Advance command) set based on the uplink signal from the base station; And performing uplink transmission to the base station by applying a TA (Timing Advance) indicated by the TA command, wherein the TA command includes at least one frequency resource region to which the TA is to be applied. It may be interpreted according to subcarrier spacing of a region.

The method may further include receiving information on a timing advertisement group (TAG) from the base station, and the TA command may be a TA command corresponding to the TAG. .

In the method according to an embodiment of the present invention, the uplink signal is a preamble for random access to the base station, and the TA command is determined by the base station for the preamble. It may be included in the random access response sent in the response.

In addition, in the method according to an embodiment of the present invention, when the TA is applied for updating a previously set uplink timing, the TA command is included in a medium access control-control element (MAC-CE) to receive the TA command. Can be. In this case, the terminal is a state in which a radio resource control connection (Radio Resource Control connection) is established, the uplink signal, a physical uplink control channel (physical uplink control channel), a physical uplink shared channel (physical uplink shared channel) ), Or a sounding reference signal.

Further, in the method according to an embodiment of the present invention, the TA command may be set based on a maximum subcarrier spacing among subcarrier intervals of frequency resource regions constituting the TAG.

In addition, in the method according to an embodiment of the present invention, the maximum TA value indicated by the TA command is a minimum subcarrier interval of subcarrier intervals of frequency resource regions constituting the TAG. minimum subcarrier spacing). In this case, a field size of the TA command may be set based on a minimum subcarrier interval among subcarrier intervals of frequency resource regions constituting the TAG.

Further, in the method according to an embodiment of the present invention, the offset between the timing of receiving the TA command and the timing of performing the uplink transmission may be set in slot units according to the subcarrier spacing.

A terminal for adjusting uplink timing in a wireless communication system according to an embodiment of the present invention, the terminal comprising: a radio frequency module (RF module) for transmitting and receiving a radio signal; And a processor operatively coupled to the RF module, the processor transmitting an uplink signal to a base station; Receiving a TA command set from the base station based on the uplink signal; And applying a TA (Timing Advance) indicated by the TA command to control uplink transmission to the base station, wherein the TA command includes at least one frequency resource region to which the TA is to be applied. It may be interpreted according to the subcarrier spacing of.

In addition, in the terminal according to an embodiment of the present invention, the processor is configured to control to receive information on a Timing Advance Group (TAG) from the base station, and the TA command is a TA command corresponding to the TAG. Can be.

Further, in the terminal according to an embodiment of the present invention, the uplink signal is a preamble for random access to the base station, and the TA command is the base station for the preamble. It may be included in the random access response sent in the response.

Further, in the terminal according to an embodiment of the present invention, when the TA is applied for updating a previously set uplink timing, the TA command is included in a medium access control-control element (MAC-CE) to receive the TA command. Can be.

Further, in the terminal according to an embodiment of the present invention, the TA command may be set based on a maximum subcarrier spacing among subcarrier intervals of frequency resource regions constituting the TAG.

In addition, in the terminal according to an embodiment of the present invention, a maximum TA value indicated by the TA command is a minimum subcarrier interval of subcarrier intervals of frequency resource regions constituting the TAG. minimum subcarrier spacing).

According to an embodiment of the present invention, even in a wireless communication system supporting a plurality of numerologies (eg, subcarrier spacing and cyclic prefix), an uplink timing may be finely adjusted.

In addition, according to an embodiment of the present invention, there is an effect of reducing the overhead of uplink timing adjustment by optimizing a field size of a TA command.

The effect obtained in the present invention is not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description. .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, describe the technical features of the present invention.
1 is a view showing an example of the overall system structure of the NR to which the method proposed in this specification can be applied.
2 illustrates a relationship between an uplink frame and a downlink frame in a wireless communication system to which the method proposed in this specification can be applied.
3 shows an example of a resource grid supported by a wireless communication system to which the method proposed in the present specification can be applied.
4 shows examples of an antenna port and a neuralology-specific resource grid to which the method proposed in this specification can be applied.
5 is a diagram illustrating an example of a self-contained slot structure to which the method proposed in the present specification can be applied.
6 shows an example of a component carrier and carrier aggregation in a wireless communication system to which the present invention can be applied.
7 shows examples of deployment scenarios considering carrier merging in an NR system.
8 is a diagram illustrating a contention based random access procedure in a wireless communication system to which the present invention can be applied.
9 is a flowchart illustrating an operation of a terminal for adjusting uplink timing in a wireless communication system to which the method proposed in the present specification can be applied.
10 illustrates a block diagram of a wireless communication device according to an embodiment of the present invention.
11 is a block diagram illustrating a communication device according to one embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The detailed description, which will be given below with reference to the accompanying drawings, is intended to explain exemplary embodiments of the present invention and is not intended to represent the only embodiments in which the present invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, one of ordinary skill in the art appreciates that the present invention may be practiced without these specific details.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention.

In this specification, a base station has a meaning as a terminal node of a network that directly communicates with a terminal. Certain operations described as performed by the base station in this document may be performed by an upper node of the base station in some cases. That is, it is apparent that various operations performed for communication with a terminal in a network composed of a plurality of network nodes including a base station may be performed by the base station or other network nodes other than the base station. A base station (BS) is a fixed station, Node B, evolved-NodeB (eNB), base transceiver system (BTS), access point (AP), next generation NB, general NB , gNodeB), and the like. In addition, a 'terminal' may be fixed or mobile, and may include a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a subscriber station (SS), and an AMS ( Advanced Mobile Station (WT), Wireless Terminal (WT), Machine-Type Communication (MTC) device, Machine-to-Machine (M2M) device, Device-to-Device (D2D) device, etc. may be replaced.

Hereinafter, downlink (DL) means communication from a base station to a terminal, and uplink (UL) means communication from a terminal to a base station. In downlink, a transmitter may be part of a base station, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of a base station.

Specific terms used in the following description are provided to help the understanding of the present invention, and the use of the specific terms may be changed to other forms without departing from the technical spirit of the present invention.

The following techniques are code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and NOMA It can be used in various radio access systems such as non-orthogonal multiple access. CDMA may be implemented by a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as global system for mobile communications (GSM) / general packet radio service (GPRS) / enhanced data rates for GSM evolution (EDGE). OFDMA may be implemented with a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, evolved UTRA (E-UTRA), or the like. UTRA is part of a universal mobile telecommunications system (UMTS). 3rd generation partnership project (3GPP) long term evolution (LTE) is part of evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink. LTE-A (advanced) is an evolution of 3GPP LTE.

In addition, 5G new radio (NR) defines Enhanced Mobile Broadband (eMBB), Massive Machine Type Communications (MMTC), Ultra-Reliable and Low Latency Communications (URLLC), and vehicle-to-everything (V2X) according to usage scenarios. .

The 5G NR standard is divided into standalone (SA) and non-standalone (NSA) according to co-existence between the NR system and the LTE system.

The 5G NR supports various subcarrier spacings, and supports CP-OFDM in downlink and CP-OFDM and DFT-s-OFDM in uplink.

Embodiments of the present invention may be supported by standard documents disclosed in at least one of the wireless access systems IEEE 802, 3GPP and 3GPP2. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document.

For clarity, the following description will focus on 3GPP LTE / LTE-A / NR (New RAT), but the technical features of the present invention are not limited thereto.

Term Definition

eLTE eNB: An eLTE eNB is an evolution of an eNB that supports connectivity to EPC and NGC.

gNB: Node that supports NR as well as connection with NGC.

New RAN: A radio access network that supports NR or E-UTRA or interacts with NGC.

Network slice: A network slice defined by the operator to provide an optimized solution for specific market scenarios that require specific requirements with end-to-end coverage.

Network function: A network function is a logical node within a network infrastructure with well-defined external interfaces and well-defined functional behavior.

NG-C: Control plane interface used for the NG2 reference point between the new RAN and NGC.

NG-U: User plane interface used for the NG3 reference point between the new RAN and NGC.

Non-standalone NR: A deployment configuration where a gNB requires an LTE eNB as an anchor for control plane connection to EPC or an eLTE eNB as an anchor for control plane connection to NGC.

Non-Standalone E-UTRA: Deployment configuration in which the eLTE eNB requires gNB as an anchor for control plane connection to NGC.

User plane gateway: The endpoint of the NG-U interface.

System general

1 is a view showing an example of the overall system structure of the NR to which the method proposed in this specification can be applied.

Referring to FIG. 1, the NG-RAN consists of gNBs that provide control plane (RRC) protocol termination for the NG-RA user plane (new AS sublayer / PDCP / RLC / MAC / PHY) and user equipment (UE). do.

The gNBs are interconnected via an Xn interface.

The gNB is also connected to the NGC via an NG interface.

More specifically, the gNB is connected to an Access and Mobility Management Function (AMF) through an N2 interface and to a User Plane Function (UPF) through an N3 interface.

NR (New Rat) Numerology and Frame Structure

)으로 스케일링(scaling) 함으로써 유도될 수 있다. 또한, 매우 높은 반송파 주파수에서 매우 낮은 서브캐리어 간격을 이용하지 않는다고 가정될지라도, 이용되는 뉴머롤로지는 주파수 대역과 독립적으로 선택될 수 있다.Multiple numerologies can be supported in an NR system. Here, the numerology may be defined by subcarrier spacing and cyclic prefix overhead. In this case, the plurality of subcarrier intervals may be represented by an integer N (or,

May be derived by scaling. Further, even if it is assumed that very low subcarrier spacing is not used at very high carrier frequencies, the used numerology may be selected independently of the frequency band.

In addition, in the NR system, various frame structures according to a number of numerologies may be supported.

Hereinafter, an Orthogonal Frequency Division Multiplexing (OFDM) numerology and frame structure that can be considered in an NR system will be described.

Multiple OFDM numerologies supported in the NR system may be defined as shown in Table 1.

의 시간 단위의 배수로 표현된다. 여기에서,

이고,

이다. 하향링크(downlink) 및 상향링크(uplink) 전송은

의 구간을 가지는 무선 프레임(radio frame)으로 구성된다. 여기에서, 무선 프레임은 각각

의 구간을 가지는 10 개의 서브프레임(subframe)들로 구성된다. 이 경우, 상향링크에 대한 한 세트의 프레임들 및 하향링크에 대한 한 세트의 프레임들이 존재할 수 있다.With regard to the frame structure in the NR system, the size of the various fields in the time domain

Is expressed as a multiple of the time unit. From here,

ego,

to be. Downlink and uplink transmissions

It consists of a radio frame having a section of (radio frame). Here, each radio frame is

It consists of 10 subframes having a section of. In this case, there may be a set of frames for uplink and a set of frames for downlink.

2 illustrates a relationship between an uplink frame and a downlink frame in a wireless communication system to which the method proposed in this specification can be applied.

이전에 시작해야 한다.As shown in FIG. 2, transmission of an uplink frame number i from a user equipment (UE) is greater than the start of the corresponding downlink frame at the corresponding UE.

You must start before.

에 대하여, 슬롯(slot)들은 서브프레임 내에서

의 증가하는 순서로 번호가 매겨지고, 무선 프레임 내에서

의 증가하는 순서로 번호가 매겨진다. 하나의 슬롯은

의 연속하는 OFDM 심볼들로 구성되고,

는, 이용되는 뉴머롤로지 및 슬롯 설정(slot configuration)에 따라 결정된다. 서브프레임에서 슬롯

의 시작은 동일 서브프레임에서 OFDM 심볼

의 시작과 시간적으로 정렬된다.Numerology

For slots, slots within a subframe

Numbered in increasing order of within a radio frame

Numbered in increasing order of. One slot

Consists of consecutive OFDM symbols of,

Is determined according to the numerology and slot configuration used. Slot in subframe

Start of OFDM symbol in the same subframe

Is aligned with the beginning of time.

* Not all UEs can transmit and receive at the same time, which means that not all OFDM symbols of a downlink slot or an uplink slot can be used.

에서의 일반(normal) CP에 대한 슬롯 당 OFDM 심볼의 수를 나타내고, 표 3은 뉴머롤로지

에서의 확장(extended) CP에 대한 슬롯 당 OFDM 심볼의 수를 나타낸다.Table 2 shows Numerology

Shows the number of OFDM symbols per slot for a normal CP in Table 3,

This indicates the number of OFDM symbols per slot for the extended CP in.

NR Physical Resource

In relation to physical resources in the NR system, an antenna port, a resource grid, a resource element, a resource block, a carrier part, etc. Can be considered.

Hereinafter, the physical resources that may be considered in the NR system will be described in detail.

First, with respect to the antenna port, the antenna port is defined so that the channel on which the symbol on the antenna port is carried can be inferred from the channel on which another symbol on the same antenna port is carried. If the large-scale property of a channel carrying a symbol on one antenna port can be deduced from the channel carrying the symbol on another antenna port, the two antenna ports are quasi co-located or QC / QCL. quasi co-location relationship. Here, the wide range characteristic includes at least one of delay spread, Doppler spread, frequency shift, average received power, and received timing.

3 shows an example of a resource grid supported by a wireless communication system to which the method proposed in the present specification can be applied.

서브캐리어들로 구성되고, 하나의 서브프레임이 14 x 2^u OFDM 심볼들로 구성되는 것을 예시적으로 기술하나, 이에 한정되는 것은 아니다. Referring to Figure 3, the resource grid is in the frequency domain

By way of example, one subframe includes 14 x 2 ^u OFDM symbols, but is not limited thereto.

서브캐리어들로 구성되는 하나 또는 그 이상의 자원 그리드들 및

의 OFDM 심볼들에 의해 설명된다. 여기에서,

이다. 상기

는 최대 전송 대역폭을 나타내고, 이는, 뉴머롤로지들뿐만 아니라 상향링크와 하향링크 간에도 달라질 수 있다.In an NR system, the transmitted signal is

One or more resource grids composed of subcarriers, and

It is described by the OFDM symbols of. From here,

to be. remind

Denotes the maximum transmission bandwidth, which may vary between uplink and downlink as well as numerologies.

및 안테나 포트 p 별로 하나의 자원 그리드가 설정될 수 있다.In this case, as shown in Figure 4, numerology

And one resource grid for each antenna port p.

4 shows examples of an antenna port and a neuralology-specific resource grid to which the method proposed in this specification can be applied.

및 안테나 포트 p에 대한 자원 그리드의 각 요소는 자원 요소(resource element)로 지칭되며, 인덱스 쌍

에 의해 고유적으로 식별된다. 여기에서,

는 주파수 영역 상의 인덱스이고,

는 서브프레임 내에서 심볼의 위치를 지칭한다. 슬롯에서 자원 요소를 지칭할 때에는, 인덱스 쌍

이 이용된다. 여기에서,

이다.Numerology

And each element of the resource grid for antenna port p is referred to as a resource element and is an index pair

Uniquely identified by From here,

Is the index on the frequency domain,

Refers to the position of a symbol within a subframe. Index pair when referring to a resource element in a slot

This is used. From here,

to be.

및 안테나 포트 p에 대한 자원 요소

는 복소 값(complex value)

에 해당한다. 혼동(confusion)될 위험이 없는 경우 혹은 특정 안테나 포트 또는 뉴머롤로지가 특정되지 않은 경우에는, 인덱스들 p 및

는 드롭(drop)될 수 있으며, 그 결과 복소 값은

또는

이 될 수 있다.Numerology

Resource elements for antenna and antenna port p

Is a complex value

Corresponds to If there is no risk of confusion, or if a specific antenna port or numerology is not specified, the indices p and

Can be dropped, so the complex value is

or

This can be

연속적인 서브캐리어들로 정의된다. 주파수 영역 상에서, 물리 자원 블록들은 0부터

까지 번호가 매겨진다. 이 때, 주파수 영역 상의 물리 자원 블록 번호(physical resource block number)

와 자원 요소들

간의 관계는 수학식 1과 같이 주어진다.In addition, the physical resource block is in the frequency domain

It is defined as consecutive subcarriers. On the frequency domain, the physical resource blocks can be zero

Are numbered until. At this time, a physical resource block number on the frequency domain

And resource elements

The relationship between is given by Equation 1.

까지 번호가 매겨진다.In addition, with respect to a carrier part, the terminal may be configured to receive or transmit using only a subset of the resource grid. At this time, the set of resource blocks set to be received or transmitted by the UE is from 0 on the frequency domain.

Are numbered until.

Self-contained slot structure

In order to minimize latency of data transmission in the TDD system, the fifth generation New RAT (NR) considers a self-contained slot structure as shown in FIG. 5.

That is, FIG. 5 is a diagram illustrating an example of a self-contained slot structure to which the method proposed in the present specification can be applied.

In FIG. 5, hatched area 510 represents a downlink control area, and black portion 520 represents an uplink control area.

The portion 530 without any indication may be used for downlink data transmission or may be used for uplink data transmission.

The feature of this structure is that DL transmission and UL transmission proceed sequentially in one slot, DL data can be transmitted in one slot, and UL Ack / Nack can also be transmitted and received.

Such a slot may be defined as a 'self-contained slot'.

That is, through such a slot structure, the base station reduces the time required to retransmit data to the terminal when a data transmission error occurs, thereby minimizing the latency of the final data transfer.

In this self-contained slot structure, the base station and the terminal need a time gap for a process of switching from a transmission mode to a reception mode or a process of switching from a reception mode to a transmission mode.

To this end, in the corresponding slot structure, some OFDM symbols at the time of switching from DL to UL are set to a guard period (GP).

Carrier Aggregation

The communication environment considered in the embodiments of the present invention includes both multi-carrier support environments. That is, a multi-carrier system or a carrier aggregation (CA) system used in the present invention means at least one having a bandwidth smaller than the target band when configuring the target broadband to support the broadband. A system that aggregates and uses a component carrier (CC).

In the present invention, the multi-carrier means the aggregation of carriers (or carrier aggregation), wherein the aggregation of carriers means not only merging between contiguous carriers but also merging between non-contiguous carriers. In addition, the number of component carriers aggregated between downlink and uplink may be set differently. The case where the number of downlink component carriers (hereinafter referred to as 'DL CC') and the number of uplink component carriers (hereinafter referred to as 'UL CC') is the same is called symmetric aggregation. This is called asymmetric aggregation. Such carrier aggregation may be used interchangeably with terms such as carrier aggregation, bandwidth aggregation, spectrum aggregation, and the like.

Carrier aggregation, in which two or more component carriers are combined, aims to support up to 100 MHz bandwidth in an LTE-A system. When combining one or more carriers having a bandwidth smaller than the target band, the bandwidth of the combining carrier may be limited to the bandwidth used by the existing system in order to maintain backward compatibility with the existing IMT system. For example, the existing 3GPP LTE system supports {1.4, 3, 5, 10, 15, 20} MHz bandwidth, and the 3GPP LTE-advanced system (i.e., LTE-A) supports the above for compatibility with the existing system. Only bandwidths can be used to support bandwidths greater than 20 MHz. In addition, the carrier aggregation system used in the present invention may support carrier aggregation by defining a new bandwidth regardless of the bandwidth used in the existing system.

The LTE-A system uses the concept of a cell to manage radio resources.

The aforementioned carrier aggregation environment may be referred to as a multiple cell environment. A cell is defined as a combination of a downlink resource (DL CC) and an uplink resource (UL CC), but the uplink resource is not an essential element. Accordingly, the cell may be configured with only downlink resources or with downlink resources and uplink resources. When a specific UE has only one configured serving cell, it may have one DL CC and one UL CC, but when a specific UE has two or more configured serving cells, as many DLs as the number of cells Has a CC and the number of UL CCs may be the same or less.

Or, conversely, DL CC and UL CC may be configured. That is, when a specific UE has a plurality of configured serving cells, a carrier aggregation environment in which a UL CC has more than the number of DL CCs may be supported. That is, carrier aggregation may be understood as merging two or more cells, each having a different carrier frequency (center frequency of a cell). Here, the term 'cell' should be distinguished from a 'cell' as an area covered by a generally used base station.

Cells used in the LTE-A system include a primary cell (PCell: Primary Cell) and a secondary cell (SCell: Secondary Cell). P cell and S cell may be used as a serving cell. In the case of the UE which is in the RRC_CONNECTED state but the carrier aggregation is not configured or does not support the carrier aggregation, there is only one serving cell consisting of the PCell. On the other hand, in case of a UE in RRC_CONNECTED state and carrier aggregation is configured, one or more serving cells may exist, and the entire serving cell includes a PCell and one or more SCells.

Serving cells (P cell and S cell) may be configured through an RRC parameter. PhysCellId is a cell's physical layer identifier and has an integer value from 0 to 503. SCellIndex is a short identifier used to identify an SCell and has an integer value from 1 to 7. ServCellIndex is a short identifier used to identify a serving cell (P cell or S cell) and has an integer value from 0 to 7. A value of 0 is applied to the Pcell, and SCellIndex is pre-assigned to apply to the Scell. That is, a cell having the smallest cell ID (or cell index) in ServCellIndex becomes a P cell.

P cell refers to a cell operating on a primary frequency (or primary CC). The UE may be used to perform an initial connection establishment process or to perform a connection re-establishment process, and may also refer to a cell indicated in a handover process. In addition, the P cell refers to a cell serving as a center of control-related communication among serving cells configured in a carrier aggregation environment. That is, the terminal may receive and transmit a PUCCH only in its own Pcell, and may use only the Pcell to acquire system information or change a monitoring procedure. E-UTRAN (Evolved Universal Terrestrial Radio Access) changes only the Pcell for the handover procedure by using an RRC ConnectionReconfigutaion message of a higher layer including mobility control information to a UE supporting a carrier aggregation environment. It may be.

The S cell may refer to a cell operating on a secondary frequency (or, secondary CC). Only one Pcell is allocated to a specific terminal, and one or more Scells may be allocated. The SCell is configurable after the RRC connection is established and can be used to provide additional radio resources. PUCCH does not exist in the remaining cells excluding the P cell, that is, the S cell, among the serving cells configured in the carrier aggregation environment. When the E-UTRAN adds the SCell to the UE supporting the carrier aggregation environment, the E-UTRAN may provide all system information related to the operation of the related cell in the RRC_CONNECTED state through a dedicated signal. The change of the system information may be controlled by the release and addition of the related SCell, and at this time, an RRC connection reconfigutaion message of a higher layer may be used. The E-UTRAN may perform dedicated signaling having different parameters for each terminal, rather than broadcasting in a related SCell.

After the initial security activation process begins, the E-UTRAN may configure a network including one or more Scells in addition to the Pcells initially configured in the connection establishment process. In the carrier aggregation environment, the Pcell and the SCell may operate as respective component carriers. In the following embodiments, the primary component carrier (PCC) may be used in the same sense as the PCell, and the secondary component carrier (SCC) may be used in the same sense as the SCell.

6 shows an example of a component carrier and carrier aggregation in a wireless communication system to which the present invention can be applied.

6 (a) shows a single carrier structure used in an LTE system. Component carriers include a DL CC and an UL CC. One component carrier may have a frequency range of 20 MHz.

6 (b) shows a carrier aggregation structure used in the LTE_A system. In the case of FIG. 6B, three component carriers having a frequency size of 20 MHz are combined. Although there are three DL CCs and three UL CCs, the number of DL CCs and UL CCs is not limited. In case of carrier aggregation, the terminal may simultaneously monitor three CCs, receive downlink signals / data, and transmit uplink signals / data.

If N DL CCs are managed in a specific cell, the network may allocate M (M ≦ N) DL CCs to the UE. In this case, the UE may monitor only M limited DL CCs and receive a DL signal. In addition, the network may assign L (L ≦ M ≦ N) DL CCs to assign a primary DL CC to the UE, in which case the UE must monitor the L DL CCs. This method can be equally applied to uplink transmission.

The linkage between the carrier frequency (or DL CC) of the downlink resource and the carrier frequency (or UL CC) of the uplink resource may be indicated by a higher layer message such as an RRC message or system information. For example, a combination of DL resources and UL resources may be configured by a linkage defined by System Information Block Type 2 (SIB2). Specifically, the linkage may mean a mapping relationship between a DL CC on which a PDCCH carrying a UL grant is transmitted and a UL CC using the UL grant, and a DL CC (or UL CC) and HARQ ACK on which data for HARQ is transmitted. It may mean a mapping relationship between UL CCs (or DL CCs) through which a / NACK signal is transmitted.

If one or more SCells are configured by the UE, the network may activate or deactivate the configured SCell (s). The PCell is always active. The network activates or deactivates the SCell (s) by sending an Activation / Deactivation MAC control element.

The active / inactive MAC control element has a fixed size and consists of a single octet comprising seven C-fields and one R-field. The C field is configured for each SCellIndex and indicates an active / inactive state of the SCell. When the C field value is set to '1', it indicates that the S cell having the corresponding S cell index is activated, and when set to '0', it indicates that the S cell having the corresponding S cell index is deactivated.

In addition, the terminal maintains a timer (sCellDeactivationTimer) for each set Scell, and deactivates the associated Scell when the timer expires. The same initial timer value is applied to each instance of the timer sCellDeactivationTimer and is set by RRC signaling. When the SCell (s) is added or after handover, the initial SCell (s) are inactive.

The terminal performs the following operation on each configured S cell (s) in each TTI.

When the terminal receives an active / inactive MAC control element for activating the SCell in a specific TTI (subframe n), the UE activates the SCell in a TTI (subframe n + 8 or later) corresponding to a predetermined timing. , (Re) start the timer related to the SCell. The UE activating the SCell means that the UE transmits a Sounding Reference Signal (SRS) on the SCell, a Channel Quality Indicator (CQI) / Precoding Matrix Indicator (PMI) / Rank Indication (RI) / Precoding Type Indicator for the SCell. ), It means that the general S-cell operation such as PDCCH monitoring on the S-cell, PDCCH monitoring for the S-cell is applied.

When the UE receives an active / inactive MAC control element for deactivating an SCell at a specific TTI (subframe n) or when a timer associated with a SCell activated for a specific TTI (subframe n) expires, the UE corresponds to a predetermined timing. Deactivate the SCell in the TTI (subframe n + 8 or later), stop the timer of the SCell, and flush all HARQ buffers associated with the SCell.

An uplink grant for an S cell in which an PDCCH on an activated S cell indicates an uplink grant or downlink assignment or a PDCCH on a serving cell that schedules an activated S cell is activated ( When indicating uplink grant or downlink assignment, the terminal restarts the timer associated with the corresponding SCell.

When the SCell is deactivated, the UE does not transmit the SRS on the SCell, does not report the CQI / PMI / RI / PTI for the SCell, does not transmit the UL-SCH on the SCell, and transmits the PDCCH on the SCell. Do not monitor.

The above-described carrier merging has been described based on the LTE / LTE-A system, but this is only for convenience of description and may be applied to the same or similarly extended to the 5G NR system. In particular, carrier merge deployment scenarios that may be considered in a 5G NR system may be as in FIG. 7.

7 shows examples of deployment scenarios considering carrier merging in an NR system.

Referring to FIG. 7, F1 and F2 represent a cell and a second frequency (or a second frequency band, a second carrier frequency, set to a first frequency (or a first frequency band, a first carrier frequency, and a first center frequency), respectively. A second center frequency).

FIG. 7A illustrates a first CA deployment scenario. As shown in (a) of FIG. 7, the F1 cell and the F2 cell may be co-located and overlaid at the same position. In this case, both layers can provide sufficient coverage, and mobility in the two layers can be supported. The scenario may include the case where the F1 cell and the F2 cell exist in the same band. In this scenario, it may be expected that aggregation may be possible between the overlapped F1 and F2 cells.

7B illustrates a second CA deployment scenario. As shown in FIG. 7B, the F1 cell and the F2 cell may exist at the same location, but the F2 cell may support smaller coverage due to a larger path loss. In this case, only the F1 cell provides sufficient coverage, and the F2 cell can be used to improve throughput. In this case, mobility may be performed based on the coverage of the F1 cell. The scenario may include a case in which the F1 cell and the F2 cell exist in different bands (eg, the F1 cell is {800MHz, 2GHz} and the F2 cell is {3.5GHz}). In that scenario, aggregation may be expected between the overlapped F1 cell and the F2 cell.

7C shows a third CA deployment scenario. As shown in FIG. 7C, the F1 cell and the F2 cell exist at the same location, but the antenna of the F2 cell may be connected to the boundary of the F2 cell to increase the throughput of the cell boundary. In this case, the F1 cell provides sufficient coverage, but the F2 cell can potentially have holes due to greater path loss or the like. In this case, mobility may be performed based on the coverage of the F1 cell. The scenario may include a case in which the F1 cell and the F2 cell exist in different bands (eg, the F1 cell is {800MHz, 2GHz} and the F2 cell is {3.5GHz}). In this scenario, the F1 cell and the F2 cell of the same base station eNB may be expected to be capable of aggregation in an area where coverage overlaps.

7 (d) shows a fourth CA deployment scenario. As shown in FIG. 7D, the F1 cell provides macro coverage, and the F2 remote radio heads (RRHs) are used to improve throughput at hot spots. Can be. In this case, mobility may be performed based on the coverage of the F1 cell. The scenario is the case where the F1 and F2 cells correspond to DL non-contiguous carriers in the same band (eg 1.7 GHz) and the bands where the F1 and F2 cells are different bands (eg F1). The cell may include {800MHz, 2GHz}, the F2 cell {3.5GHz}). In that scenario, the F2 cells (ie RRHs) may be expected to be able to merge with the underlying F1 cell (ie macro cell) (s).

7 (e) shows a fifth CA deployment scenario. The scenario is similar to the second CA deployment scenario described above, but frequency selective repeaters may be deployed such that coverage for one of the carrier frequencies can be extended. In this scenario, the F1 cell and the F2 cell of the same base station may be expected to be merged in an area where coverage overlaps.

By different serving cells, but in the physical layer of UL grants and DL assignments for the same TTI (e.g., in the number of control symbols, propagation and deployment scenarios). Receive timing differences (depending on) may not affect MAC operation. The UE may need to process a relative propagation delay difference of up to 30us among CCs to be merged in both intra-band discontinuous CA and inter-band discontinuous CS. This may mean that since the time alignment of the base station is specified to a maximum of 0.26us, the terminal needs to process a delay spread of up to 30.26us among CCs monitored by the receiver. In addition, this may mean that the terminal must process a maximum uplink transmission timing difference between TAGs of 36.37us for an inter-band CA having a plurality of TAGs.

When a CA is deployed, frame timing and system frame number (SFN) can be aligned across the merged cells.

Random Access Procedure

Hereinafter, a random access procedure provided by the LTE / LTE-A system will be described.

The random access procedure is used for the terminal to obtain uplink synchronization with the base station or to receive uplink radio resources. After the terminal is powered on, the terminal acquires downlink synchronization with the initial cell and receives system information. From the system information, a set of available random access preambles and information about radio resources used for transmission of the random access preambles are obtained. The radio resource used for the transmission of the random access preamble may be specified by a combination of at least one subframe index and an index on the frequency domain. The terminal transmits a random access preamble selected randomly from the set of random access preambles, and the base station receiving the random access preamble sends a timing alignment value for uplink synchronization to the terminal through a random access response. As a result, the terminal acquires uplink synchronization.

The random access procedure is a common procedure in frequency division duplex (FDD) and time division duplex (TDD). The random access procedure is irrelevant to the cell size, and is independent of the number of serving cells when carrier aggregation (CA) is configured.

First, a case in which the UE performs a random access procedure may be as follows.

When the terminal performs the initial access (initial access) in the RRC idle state because there is no RRC connection (RRC Connection) with the base station

When performing the RRC connection re-establishment procedure

When the UE first accesses the target cell during the handover process

When the random access procedure is requested by the command of the base station

In case of data to be transmitted in downlink during non-synchronized uplink time synchronization during RRC connection state

*

When there is data to be transmitted on the uplink in a situation in which the uplink time is not synchronized (non-synchronized) or the designated radio resource used for requesting the radio resource is not allocated during the RRC connection state.

In the case of performing positioning of the UE in a situation in which timing advance is needed during the RRC connection state

When performing recovery process in case of radio link failure or handover failure

In 3GPP Rel-10, a common consideration is to apply a timing advance (TA) value applicable to one specific cell (eg, a Pcell) to a plurality of cells in a wireless access system supporting carrier aggregation. However, the UE may merge a plurality of cells belonging to different frequency bands (that is, largely spaced on the frequency) or a plurality of cells having different propagation characteristics. In addition, in the case of a specific cell, a small cell or secondary base station such as a remote radio header (RRH) (ie, a repeater), a femto cell, or a pico cell may be used to expand coverage or remove coverage holes. In a situation where a secondary eNB (SeNB) is disposed in a cell, the terminal communicates with a base station (ie, a macro eNB) through one cell, and when communicating with a secondary base station through another cell, Cells may have different propagation delay characteristics. In this case, when uplink transmission using a single TA value in a common manner may be seriously influenced on synchronization of an uplink signal transmitted on a plurality of cells. Therefore, it may be desirable to have a plurality of TAs in a CA situation in which a plurality of cells are merged, and in 3GPP Rel-11, it is considered that an TA is independently allocated to a specific cell group unit to support multiple TAs. do. This is called a TA group (TAG: TA group). The TAG may include one or more cells, and the same TA may be commonly applied to one or more cells included in the TAG. In order to support such multiple TAs, the MAC TA command control element is composed of a 2-bit TAG identifier (TAG ID) and a 6-bit TA command field.

When the UE for which carrier aggregation is configured performs the random access procedure described above with respect to the PCell, the UE performs the random access procedure. In the case of a TAG (ie, a pTAG: primary TAG) to which a Pcell belongs, all cell (s) in the pTAG are replaced with TAs determined based on the Pcell or adjusted through a random access procedure accompanying the Pcell. Applicable to On the other hand, in the case of a TAG (ie, sTAG: secondary TAG) composed only of S cells, a TA determined based on a specific S cell in the sTAG may be applied to all cell (s) in the sTAG, where TA is a base station. Can be obtained by a random access procedure. Specifically, the SCell is configured as a RACH (Random Access Channel) resource in the sTAG, and the base station requests the RACH access from the SCell to determine the TA. That is, the base station initiates the RACH transmission on the S cells by the PDCCH order transmitted in the P cell. The response message for the SCell preamble is transmitted through the Pcell using the RA-RNTI. The UE may apply the TA determined based on the SCell that has successfully completed the random access to all cell (s) in the corresponding sTAG. As such, the random access procedure may be performed in the SCell to obtain a timing alignment of the sTAG to which the SCell belongs.

In the LTE / LTE-A system, in the process of selecting a random access preamble (RACH preamble), a contention-based random access procedure in which the UE randomly selects and uses one preamble within a specific set And a non-contention based random access procedure using a random access preamble allocated by a base station only to a specific terminal. However, the non- contention based random access procedure may be used only for the terminal positioning and / or the timing advance alignment for the sTAG when requested by the above-described handover procedure and the command of the base station. After the random access procedure is completed, general uplink / downlink transmission occurs.

Meanwhile, a relay node (RN) also supports both a contention-based random access procedure and a contention-free random access procedure. When the relay node performs a random access procedure, it suspends the RN subframe configuration at that point. In other words, this means temporarily discarding the RN subframe configuration. Thereafter, the RN subframe configuration is resumed at the time when the random access procedure is successfully completed.

8 is a diagram illustrating a contention based random access procedure in a wireless communication system to which the present invention can be applied.

(1) first message (Msg 1, message 1)

First, the UE randomly selects one random access preamble (RACH preamble) from a set of random access preambles indicated through system information or a handover command, and A physical RACH (PRACH) resource capable of transmitting a random access preamble is selected and transmitted.

The random access preamble is transmitted in 6 bits in the RACH transmission channel, and the 6 bits are 5 bits of a random identity for identifying a UE having transmitted the RACH, and 1 bit (eg, a third for indicating additional information). Message (indicating the size of Msg 3).

The base station receiving the random access preamble from the terminal decodes the preamble and obtains an RA-RNTI. The RA-RNTI associated with the PRACH in which the random access preamble is transmitted is determined according to the time-frequency resource of the random access preamble transmitted by the corresponding UE.

(2) a second message (Msg 2, message 2)

The base station transmits a random access response addressed to the RA-RNTI obtained through the preamble on the first message to the terminal. The random access response includes a random access preamble index / identifier (UL preamble index / identifier), an UL grant indicating an uplink radio resource, a temporary cell identifier (TC-RNTI), and a time synchronization value. (TAC: time alignment commands) may be included. The TAC is information indicating a time synchronization value that the base station sends to the terminal to maintain uplink time alignment. The terminal updates the uplink transmission timing by using the time synchronization value. When the terminal updates the time synchronization, a time alignment timer is started or restarted. The UL grant includes an uplink resource allocation and a transmit power command (TPC) used for transmission of a scheduling message (third message), which will be described later. TPC is used to determine the transmit power for the scheduled PUSCH.

After the UE transmits the random access preamble, the base station attempts to receive its random access response within a random access response window indicated by the system information or the handover command, and PRACH The PDCCH masked with the RA-RNTI corresponding to the PDCCH is detected, and the PDSCH indicated by the detected PDCCH is received. The random access response information may be transmitted in the form of a MAC packet data unit (MAC PDU), and the MAC PDU may be transmitted through a PDSCH. The PDCCH preferably includes information of a terminal that should receive the PDSCH, frequency and time information of a radio resource of the PDSCH, a transmission format of the PDSCH, and the like. As described above, once the UE successfully detects the PDCCH transmitted to the UE, the UE may properly receive the random access response transmitted to the PDSCH according to the information of the PDCCH.

The random access response window refers to a maximum time period in which a terminal transmitting a preamble waits to receive a random access response message. The random access response window has a length of 'ra-ResponseWindowSize' starting from three subframes after the last subframe in which the preamble is transmitted. That is, the UE waits to receive a random access response during the random access window obtained after three subframes from the subframe in which the preamble is terminated. The terminal may acquire a random access window size ('ra-ResponseWindowsize') parameter value through system information, and the random access window size may be determined as a value between 2 and 10.

If the terminal successfully receives a random access response having the same random access preamble identifier / identifier as the random access preamble transmitted to the base station, the monitoring stops the random access response. On the other hand, if the random access response message is not received until the random access response window ends, or if a valid random access response having the same random access preamble identifier as the random access preamble transmitted to the base station is not received, the random access response is received. Is considered to have failed, and then the UE may perform preamble retransmission.

As described above, the reason why the random access preamble identifier is needed in the random access response is that the UL grant, the TC-RNTI, and the TAC are used by any terminal because one random access response may include random access response information for one or more terminals. It is necessary to tell the validity.

(3) third message (Msg 3, message 3)

When the terminal receives a valid random access response to the terminal, it processes each of the information included in the random access response. That is, the terminal applies the TAC, and stores the TC-RNTI. In addition, by using the UL grant, the data stored in the buffer of the terminal or newly generated data is transmitted to the base station. In the case of initial access of the UE, an RRC connection request generated in the RRC layer and delivered through the CCCH may be included in the third message and transmitted, and in the case of an RRC connection reestablishment procedure, an RRC generated in the RRC layer and delivered through the CCCH The connection reestablishment request may be included in the third message and transmitted. It may also include a NAS connection request message.

The third message should include the identifier of the terminal. In the contention-based random access procedure, it is not possible to determine which terminals perform the random access procedure in the base station, because the terminal needs to be identified for future collision resolution.

There are two methods for including the identifier of the terminal. In the first method, if the UE has a valid cell identifier (C-RNTI) allocated in the corresponding cell before the random access procedure, the UE transmits its cell identifier through an uplink transmission signal corresponding to the UL grant. do. On the other hand, if a valid cell identifier has not been assigned before the random access procedure, the UE transmits its own unique identifier (eg, S-TMSI or random number). In general, the unique identifier is longer than the C-RNTI. Terminal specific scrambling is used for transmission on the UL-SCH. However, if the UE has not yet been assigned a C-RNTI, scrambling cannot be based on the C-RNTI, and the TC-RNTI received in the random access response is used instead. If the UE transmits data corresponding to the UL grant, it starts a timer for contention resolution (contention resolution timer).

(4) Fourth message (Msg 4, message 4)

When the base station receives the C-RNTI of the terminal through the third message from the terminal, the base station transmits a fourth message to the terminal using the received C-RNTI. On the contrary, when the unique identifier (ie, S-TMSI or random number) is received from the terminal through the third message, the fourth message is transmitted using the TC-RNTI allocated to the terminal in the random access response. Send to the terminal. Here, the fourth message may correspond to an RRC connection setup message including the C-RNTI.

After transmitting the data including its identifier through the UL grant included in the random access response, the terminal waits for instructions from the base station to resolve the collision. That is, it attempts to receive a PDCCH to receive a specific message. Two methods exist in the method of receiving the PDCCH. As mentioned above, if the third message transmitted corresponding to the UL grant is its C-RNTI, it attempts to receive the PDCCH using its C-RNTI, and the identifier is a unique identifier (ie, In the case of S-TMSI or a random number, it attempts to receive the PDCCH using the TC-RNTI included in the random access response. Then, in the former case, if the PDCCH is received through its C-RNTI before the conflict resolution timer expires, the terminal determines that the random access procedure has been normally performed, and terminates the random access procedure. In the latter case, if the PDCCH is received through the TC-RNTI before the conflict resolution timer expires, the data transmitted by the PDSCH indicated by the PDCCH is checked. If the unique identifier is included in the content of the data, the terminal determines that the random access procedure is normally performed, and terminates the random access procedure. The terminal acquires the C-RNTI through the fourth message, and then the terminal and the network transmit and receive a terminal specific message using the C-RNTI.

The following describes a method for solving "collision" in random access.

The reason for collision in performing random access is basically because the number of random access preambles is finite. That is, since the base station cannot grant the UE-specific random access preamble to all the UEs, the UE randomly selects and transmits one of the common random access preambles. Accordingly, when two or more terminals select and transmit the same random access preamble through the same radio resource (PRACH resource), the base station determines that one random access preamble is transmitted from one terminal. For this reason, the base station transmits a random access response to the terminal and predicts that the random access response will be received by one terminal. However, as described above, since collision may occur, two or more terminals receive one random access response, and thus, each terminal performs an operation according to reception of a random access response. That is, using one UL Grant included in the random access response, there is a problem that two or more terminals transmit different data to the same radio resource. Accordingly, all of the data transmission may fail, or only the data of a specific terminal may be received at the base station according to the location or transmission power of the terminals. In the latter case, since two or more terminals assume that the transmission of their data has been successful, the base station should inform the terminals that have failed in the contention about the fact of the failure. That is, to inform the information about the failure or success of the competition is called contention resolution.

There are two methods of collision resolution. One method is to use a contention resolution timer and the other method is to transmit identifiers of successful terminals to the terminals. The former case is used when the terminal already has a unique C-RNTI before the random access procedure. That is, the terminal that already has the C-RNTI transmits data including its C-RNTI to the base station according to the random access response, and operates the "collision resolution" timer. When the PDCCH information indicated by the C-RNTI is received before the "collision resolution" timer expires, the terminal determines that it has succeeded in the competition, and ends the random access normally. On the contrary, if the CDC does not transmit the PDCCH indicated by its C-RNTI before the "Conflict Resolution" timer expires, it is determined that it has failed in the race, the random access procedure is performed again, or the higher layer fails. Can be informed. In the latter case, the method of transmitting an identifier of a successful terminal is used when the terminal does not have a unique cell identifier before the random access procedure. That is, when the terminal itself does not have a cell identifier, the terminal transmits data including an identifier higher than the cell identifier (S-TMSI or random number) according to the UL Grant information included in the random access response, and the terminal operates the conflict resolution solution timer. Let's do it. If the data including its own higher identifier is transmitted to the DL-SCH before the collision_resolved_timer expires, the terminal determines that the random access procedure is successful. On the other hand, before the "collision resolution" timer expires, if the data including its higher identifier is not transmitted to the DL-SCH, the UE determines that the random access procedure has failed.

Meanwhile, unlike the contention-based random access procedure illustrated in FIG. 8, the random access procedure is terminated by only transmitting the first message and transmitting the second message. However, before the terminal transmits the random access preamble to the base station as the first message, the terminal is allocated a random access preamble from the base station, and transmits the allocated random access preamble to the base station as a first message and from the base station. The random access procedure is terminated by receiving the random access response.

The above-described random access procedure has been described with reference to the LTE / LTE-A system, but this is only for convenience of description and may be applied to the 5G NR system in the same or similar manner.

As discussed above, in 5G NR systems (hereinafter NR systems) various use case scenarios and / or deployments in various frequency bands may be considered. Accordingly, in the NR system, a method of supporting various numerologies for each component carrier (CC) may be considered. Here, the numerology may mean a subcarrier spacing and a cyclic prefix (CP).

In view of the above, in the present specification, timing adjustment, that is, transmission / reception timing adjustment, is supported in a carrier aggregation (CA) situation of NR systems in which numerology may be different per CC and / or between CCs. Suggest how to.

Timing Advance (TA) referred to herein refers to an uplink subframe (UL subframe) and an uplink subframe (DL subframe) for performing orthogonal uplink / downlink transmission and reception at a base station. It may mean a timing offset applied (or applied) by the terminal for the purpose of synchronizing downlink subframes (DL subframes).

In the NR system, a plurality of TAGs (Timing Advance Groups), that is, multiple TAGs, may be supported in consideration of the aforementioned CA deployment scenario (eg, the fourth CA deployment scenario (HetNet)). As described above, a TAG including a PCell among the TAGs may be referred to as a pTAG, and a TAG composed of only the SCell may be referred to as an sTAG.

In this case, initial timing information about the initial pTAG may be obtained through a random access procedure (RA procedure). Subsequently, the timing information for the sTAG is considered to be a state in which the UE is in an RRC connection (RRC connection) setup state (that is, RR_CONNECTED state), and is based on a non-PDCCH (or NPDCCH) order. It can be obtained through a contention-free RA procedure or a non-contention RA procedure.

Hereinafter, in consideration of the CA (Carrier Aggregation operation) operation in the above-described NR system, in the present specification, a method for obtaining pTAG timing information, a method for obtaining sTAG timing information, and a method for setting a TA command The method of setting the activation / reactivation timing of the SCell and the method of determining a timing difference requirement for the timing difference will be described in detail.

First embodiment

In the present embodiment, a method of obtaining pTAG timing information in consideration of CA operation in an NR system will be described.

In this case, a random access procedure (hereinafter, referred to as an RA procedure) may be used as a method for obtaining pTAG timing information in consideration of CA operation in the NR system.

Specifically, in order to acquire TA information for the pTAG, the RA procedure needs to be performed starting with transmitting a random access preamble (hereinafter referred to as RA preamble) to the PCell. At this time, a contention-based RA procedure or a contention-free RA procedure may be used as an RA procedure for acquiring TA information for pTAGH.

For CA operation in an NR system, the difference in the number of components (e.g. subcarrier spacing 15 kHz, 30 kHz, 60 kHz, 120 kHz) can be selected from the various values of the CC (Component Carrier). have. For example, the lengths of symbols, slots, and / or subframes may be set differently according to the difference in subcarrier spacing, and accordingly, transmission timing and counter size at different stages set differently. ), Etc., need to be considered.

Hereinafter, a method 1-1) using a competition-based RA procedure and a method 1-2) using a non-competition-based RA procedure will be described in detail with respect to a procedure for obtaining pTAG timing information. Method 1) and method 2) are merely divided for convenience of description, and may be applied to each other by being replaced with some components.

Method 1-1)

First, a method of obtaining pTAG timing information using a contention-based RA procedure will be described.

In a contention-based RA procedure, when a base station (eg, gNB) successfully receives a preamble (that is, Msg 1 described above) transmitted by the UE in the first step, the base station (eg, gNB) receives a constant from the transmission start point of the preamble (eg, nth subframe). A RAR message (message of the second stage, that is, Msg 2 described above) may be transmitted to the UE in a RAR window starting after time. Here, the start point and the end point of the RAR window may be set in units of subframes and / or slots.

For example, the RAR window may be set to start at the n + k0 th subframe. In this case, n may be a transmission start subframe of the preamble or may correspond to the last subframe. However, in this case, the preparation time required for the RAR transmission at the base station by scaling the absolute time corresponding to k0 (ie, expanding or reducing according to a specific condition / value) according to the CC's neurology. This lack or, conversely, excessively long time may cause disadvantages in terms of latency or power.

In order to solve such a problem, the k0 value may be set in absolute time, or the RAR window timing may be set in units of symbols, slots, and / or subframes that are set in conjunction with or independently of the numerology. In this case, the set value may be commonly applied to all of the neurology, or may be a value applied differently to each of the neurology. For example, in the method of setting the RAR window timing in conjunction with the above-mentioned numerology, when the subcarrier interval increases by M times, the length of the subframe is reduced to 1 / M. The method may be interpreted as a frame.

Alternatively, for example, the RAR message (ie, Msg 2) transmitted from the base station to the terminal in the RAR window may be configured to be transmitted in the n + k1 th subframe. Even in this case, n may be a transmission start subframe of the preamble, or may correspond to the last subframe, and a symbol, a slot, and / or a sub-k1 value is set to absolute time, or is set in conjunction with or independently of the numerology. The RAR window timing may be set in units of frames. Similar to the above example, the set value may be a value applied in common to all the neurology, or may be differently applied to each of the neurology. For example, in the method of setting the RAR transmission timing in conjunction with the above-mentioned numerology, when the subcarrier interval increases by M times, the length of the subframe is reduced to 1 / M, and the RAR transmission start point is set to k1 * M sub. The method may be interpreted as a frame.

The UE may transmit a message of the third step (ie, Msg 3 described above) after a predetermined time from the RAR receiving subframe (that is, the subframe receiving the RAR). For example, assuming that the RAR reception subframe is the nth subframe, the UE may be configured to transmit a message of the third step in the n + k2th subframe.

In this case, similar to k0 and / or k1 described above, the k2 value may be set to absolute time, or may be set to the message of the third step in units of symbols, slots, and / or subframes that are set in conjunction with or independently of the neurology. The window timing can be set. Similar to the above example, the set value may be a value applied in common to all the neurology, or may be differently applied to each of the neurology. For example, in the method of setting the transmission timing for Msg 3 in conjunction with the above-described numerology, when the subcarrier interval increases by M times, the length of the subframe is reduced to 1 / M. It may be a method of interpreting a starting point as a k2 * M subframe.

Method 1-2)

Next, a method of obtaining pTAG timing information using a non-competition based RA procedure will be described.

When the terminal receives information on the PDCCH order (eg, PDCCH order) from the base station (eg, gNB), the terminal is generated (or allocated) after a certain time from the subframe (eg, the nth subframe) to which the PDCCH order belongs. A message of the first step (ie, Msg 1) may be transmitted through the PDCCH resource. Here, the minimum value of the transmission timing of the message of the first step (ie, the transmission timing for Msg 1) may be set in units of subframes.

For example, the UE may be configured to transmit the preamble through the PRACH resource of the earliest time point starting from or after the n + k0 th subframe. Since the subframe length is set differently according to CC's numerology, an absolute time corresponding to k0 is scaled (that is, enlarged or reduced according to a specific condition / value) and is required for transmission of a preamble from the terminal. This can lead to insufficient preparation time or, conversely, an excessively long time, which can be disadvantageous in terms of delay or power.

In order to solve this problem, the k0 value may be set in absolute time, or may be set in units of symbols, slots, and / or subframes set in conjunction with or independently of the neurology. In this case, the set value may be commonly applied to all of the neurology, or may be a value applied differently to each of the neurology. For example, the method of setting the k0 value in conjunction with the above-mentioned numerology may include a message of the first step (ie, Msg) in consideration of the fact that the subframe length is reduced to 1 / M when the subcarrier interval is increased by M times. 1) It may be a method of interpreting a start point of transmission as a k0 * M subframe.

Similarly to the method 1) described above, also in the case of the method 2), the RAR window setting and the RAR transmission timing are set to absolute time, linked to the numerology or independently set symbols, slots, and / or subs. It may be set in units of frames. Even in this case, the set value may be commonly applied to all of the neurology or may be a value applied differently to each of the neurology.

In addition, similarly to the method 1) described above, in the case of the method 2), the transmission timing of the message of the third step (i.e., Msg 3) is set to an absolute time, or is linked to the numerology or independently. It may be set in units of one symbol, slot, and / or subframe. Even in this case, the set value may be commonly applied to all of the neurology or may be a value applied differently to each of the neurology.

Second embodiment

In the present embodiment, a method of obtaining sTAG timing information in consideration of CA operation in an NR system will be described.

Similar to the first embodiment described above, a random access procedure (hereinafter, referred to as RA procedure) may be used as a method for obtaining sTAG timing information in consideration of CA operation in an NR system.

Specifically, the terminal performs a timing adjustment (in particular, uplink timing adjustment) through an RA procedure for the PCell belonging to the pTAG, and then enters an RRC connection setup state (RRC connection setup state, RRC_CONNECTED state). Can be. Thereafter, the SCell may be activated through a SCell addition procedure for the configured SCell. In this process, the base station (eg, gNB) may signal to the terminal whether the corresponding SCell belongs to the pTAG or sTAG.

When the SCell belongs to the pTAG, the same TA command as the PCell may be shared. Otherwise, if the corresponding SCell belongs to the sTAG, the terminal may perform the RA procedure for the activated SCell to obtain timing information for the sTAG.

At this time, the RA procedure performed by the UE may be initiated by transmitting a PDCCH order because the UE is already in an RRC connection setup state. Here, the PDCCH order may be for a SCell to obtain timing information or for another activated SCell (ie, scheduled SCell) belonging to the same sTAG as the corresponding SCell.

In consideration of the PDCCH order by self-carrier scheduling, it may be assumed that the PDCCH order is received from the SCell in which the UE transmits a preamble (ie, RA preamble).

In this case, when the terminal receives the PDCCH order from the base station, the terminal receives the message of the first step through the PDCCH resources occurring (or allocated) after a certain time from the subframe (eg, the n-th subframe) to which the PDCCH order belongs (Ie, Msg 1) can be transmitted. Here, the minimum value of the transmission timing of the message of the first step (ie, the transmission timing for Msg 1) may be set in units of subframes.

For example, the UE may be configured to transmit the preamble through the PRACH resource of the earliest time point starting from or after the n + k0 th subframe.

In addition, for a similar reason as in the case of the method 2) of the first embodiment, the k0 value may be set in absolute time, or may be set in units of symbols, slots, and / or subframes that are set independently or in conjunction with a numerology. have. In this case, the set value may be commonly applied to all of the neurology, or may be a value applied differently to each of the neurology. For example, the method of setting the k0 value in conjunction with the above-mentioned numerology may include a message of the first step (ie, Msg) in consideration of the fact that the subframe length is reduced to 1 / M when the subcarrier interval is increased by M times. 1) It may be a method of interpreting a start point of transmission as a k0 * M subframe.

Similarly to the method 1) of the first embodiment described above, in this case, too, the RAR window setting and the RAR transmission timing are set to absolute time, symbols, slots, and / or set in conjunction with or independently of the numerology. It may be set in units of subframes. In this case, the set value may be commonly applied to all of the neurology, or may be a value applied differently to each of the neurology.

In addition, similarly to the method 1) of the first embodiment described above, in this case as well, the transmission timing of the message of the third stage (i.e., Msg 3) is set to an absolute time, or linked to or independently of the neurology. It may be set in units of configured symbols, slots, and / or subframes. In this case, the set value may be commonly applied to all of the neurology, or may be a value applied differently to each of the neurology.

Before the UE performs the RA procedure for the SCell to acquire TA information for the sTAG, timings (eg, Msg 1 transmission timing, RAR window timing, and RAR transmission at each stage are already performed through the RA procedure for the PCell). Timing, Msg 3 transmission timing) can be determined. Therefore, in this case, the timing at each step of the RA procedure for the pTAG can be equally applied to the RA procedure for the SCell. Alternatively, the terminal may set and use timing at each step separately from the PCell according to the above-described method. Alternatively, the timing of each step of the RA procedure for the pTAG may be equally applied to a case where the SCell and the PCell of which the desired to obtain TA information are the same or correspond to a specific combination.

Third embodiment

In the present embodiment, a method of setting a TA command in consideration of CA operation in an NR system will be described.

First, an initial timing adjustment procedure in the NR system may be performed as follows.

The base station estimates an initial TA from a preamble (ie, RA preamble) transmitted by the UE, and then transmits a TA command to the UE in a next step (ie, RAR transmission step). Thereafter, the UE adjusts the transmission timing of the third step message (ie, Msg 3) to the initial TA received through the TA command, and transmits it, and may enter (or reach) the RRC connection establishment state through the remaining RA procedures. have.

When the UE enters the RRC connection configuration state, TA tracking may be performed through a specific uplink signal (for example, PUSCH, PUCCH, SRS, etc.). Here, the TA tracking may refer to an operation of determining whether the TA needs to be modified or updated based on an uplink signal transmitted by the UE.

If it is determined that modification or update of the TA is necessary, the base station transmits a TA command medium access control-control element (MAC-CE) to the terminal, and the terminal can perform the TA correction (or correction, update). Can be instructed. Here, the TA command MAC-CE may refer to a message configured to transmit a TA command in the MAC layer.

At this time, the time (that is, offset) from the timing of receiving the TA command to the timing of first correction in the uplink subframe (or slot) using the received TA value is in units of subframes (or slots). Can be set. For example, when the UE receives the TA command in the nth subframe, the UE may be configured to perform uplink transmission by reflecting the TA command received from the n + kth subframe. Since the subframe units may be scaled (ie, enlarged or reduced) according to the subcarrier interval, the timing reflecting the TA command is set to absolute time, symbols, slots, and / or independently set in conjunction with the numerology. Alternatively, it may be set in units of subframes. The TA command may be set in consideration of the maximum supportable cell radius, control in a cyclic prefix (CP), and the like.

Specifically, the TA command in the above-described NR system may be configured using at least one of the following methods 3-1) to 3-3). Here, the method 3-1) to the method 3-3) are only divided for convenience of description, and of course, they may be applied to each other by being replaced with some components.

For reference, since a cell may be allocated to a specific frequency resource region, the frequency resource region referred to in this embodiment may be interpreted as a concept corresponding to the cell. For example, in the present specification, the neuronology of a specific cell may have the same meaning as that of the neurology set in a specific frequency resource region.

In addition, in the present embodiment, the unit of the TA command may mean a TA value indicated by the TA command or a unit of the corresponding value, and may also mean a unit in which the terminal receives or interprets the TA command.

Method 3-1)

First, the unit of the TA command may be set to an absolute time (eg, microseconds (us), etc.). That is, the TA value or the unit of the TA value indicated by the TA command may be expressed in absolute time.

In this case, the maximum TA value (which is related to the size of the TA field) may be set to a fixed value. In addition, the method can be applied equally to all neurology.

Method 3-2)

Next, the unit of the TA command may be interpreted in association with the neuralology of the frequency resource region (eg, cell, CC, etc.) to which the TA is to be applied. That is, the TA command may be interpreted (scaled) according to the neuralology of the frequency resource region to which the TA is to be applied.

In this case, the maximum TA value (which is related to the size of the TA field) may be set to a fixed value or may be set by the base station. In the case of the scheme set by the base station, the maximum TA value may be transmitted as system information (SI) through broadcasted information (for example, a system information block (SIB), etc.). .

For example, the method may mean a method of interpreting the value of the TA indicated by the TA command by scaling (ie, expanding or contracting) the subcarrier interval.

Method 3-3)

Next, the unit of the TA command is determined by the base station, and information about the TA command may be broadcast through system information (eg, a system information block). That is, the base station sets a unit of a TA command, and information about the TA command can be transmitted through a system information block.

In this case, the maximum TA value (which is related to the size of the TA field) may also be set by the base station or set to a fixed value. In the method, the system information block may be implicitly indicated through a PRACH format configuration.

In the following examples, the selection or application of the methods 3-1) to 3-3) described above may be considered differently.

For example, look at the case of the TA in the RAR received in the initial random access procedure (RA). In this case, since the base station cannot assume what state the terminal is in (eg, an RRC configuration connection state), the above-described method 3-1) may be applied. Alternatively, the above-described method 3-2 based on an operating or a specific neurology (eg, reference numerology) may be applied.

That is, in the case of the initial RA procedure, how absolute time is set for a TA command and / or the TA command is a numerology, in particular a numerol in the frequency resource region (eg, the frequency region corresponding to a particular cell) to which the TA is to be applied. The method of setting may be applied accordingly.

For another example, look at the case of the TA in the MAC-CE received for uplink sync adjustment in the terminal connected state (eg, RRC connection configuration state). In this case, since the base station knows that the state of the terminal is in the RRC connection configuration state, the above-described method 3-2 considering the neurology may be applied. Alternatively, the above-described method 3-3) may be applied for flexibility of TA command setting.

That is, when the terminal has already completed the RRC connection setup with the base station, the TA command transmitted by the base station may be interpreted according to the numerology of the frequency resource region to which the corresponding TA is to be applied. At this time, when the TA is applied for updating the previously set uplink timing (for example, uplink synchronization adjustment by TA tracking, etc.), a TA command indicating the corresponding TA may be included in the MAC-CE and transmitted to the UE. have.

For another example, look at the case of the TA in the RAR received in the RA procedure for the purpose of scheduling request (SR) in the connected state (eg, RRC connection setup state). In this case, since the base station cannot assume what state the terminal is in (eg, an RRC configuration connection state), the above-described method 3-1) may be applied. Alternatively, the above-described method 3-2) based on an operation or a specific neurology (eg, reference numerology) may be applied.

As another example, a case of a TA in an RAR received in a PDCCH order based RA procedure (eg, a non-competition based RA procedure) will be described. In this case, in this case, since the base station knows that the state of the terminal is the RRC connection setup state, the above-described method 3-2) taking into account the numerology may be applied. Alternatively, the above-described method 3-3) may be applied for flexibility of TA command setting.

In addition, when the base station knows the numerology of the terminal (ie, the numerology applied by the terminal to perform uplink transmission) (for example, in the case of the first example and / or the second example described above), the TA The method of setting a command (ie, a unit of a TA command), and / or a maximum TA value (which is related to the size of a TA field) will be described in detail.

In this case, if the numerology between the frequency resource regions (eg, cells) constituting the TAG is different, the TA command and / or the maximum TA value may be determined by a particular numerology belonging to the TAG (eg, a maximum subcarrier spacing. In other words, when a TAG is composed of multiple numerologies, the TA command and / or the maximum TA value for the TAG may be set or interpreted according to the specific numerology constituting the TAG. Such a method may be performed as in the following example.

For example, when the above-described method 3-2) or method 3-3) is selected and applied, a method of setting based on a specific subcarrier interval belonging to a TAG may be considered. That is, a criterion for setting or interpreting a range of a TA command may be set to a specific subcarrier interval among a plurality of subcarrier intervals belonging to the corresponding TAG.

In particular, the unit of the TA command may be set in the maximum subcarrier interval unit, and / or the maximum TA value may be set in the minimum subcarrier interval unit. Here, the maximum subcarrier interval and the minimum subcarrier interval may mean the maximum value and the minimum value among the subcarrier intervals of the plurality of resource regions constituting the corresponding TAG, respectively.

In this regard, the existing LTE system supports only 15KHz subcarrier interval, and the unit of TA command is fixed at 16Ts (1Ts = 1 / (30.72MHz) ~ = 0.0325us). Therefore, considering the length 144Ts (or 160Ts) of the general CP of the LTE system, the ratio of the TA command unit and the CP length is 16/144 = 1/9, and thus there are about 9 TA command units in the general CP. do. For example, if the TA command unit 16Ts of the LTE system is applied to the case where the subcarrier intervals of the frequency resource regions (eg, cells) constituting the TAG in the NR system are 15 KHz and 60 KHz, respectively, the frequency using the 60 KHz subcarrier interval is used. In the resource area, the TA command is reduced to 1/4 the CP length with 16Ts. In this case, the ratio of the TA command unit and the CP length becomes 16 / (144/4) = 4/9, so that only about two TA adjustment units exist in the CP, and thus, fine tuning of the TA is virtually impossible. Done.

In particular, the problem may be more severe when frequency resource regions (eg, cells) using subcarrier spacings of 15 KHz and 120 KHz exist within the same TAG. In the case of a frequency resource region (eg, a cell) using a 120 KHz subcarrier interval, since there is one TA adjustment unit in the CP, the TA adjustment itself becomes virtually impossible.

In order to solve this problem, by setting the above-described TA command (ie, TA command unit) in the maximum subcarrier interval unit, at least LTE for all frequency resource regions (eg, cells) constituting the TAG regardless of the numerology. It can support system-level TA fine tuning. For example, in this manner, about 9 TA command units may be set in the CP length.

On the other hand, the CP length is inversely proportional to the subcarrier spacing when the CP overhead is the same. This is because the length of the effective interval of the OFDM symbol is inversely proportional to the subcarrier interval, so that when the CP overhead (that is, the ratio of the CP length to the OFDM symbol validity interval) is constant, the CP length also increases in inverse proportion to the subcarrier interval. Because.

Accordingly, as described above, when the numerology of the frequency resource regions (eg, cells) constituting the TAG is different, the TA command may express up to the CP range of the frequency resource region (eg, a cell) having the minimum subcarrier interval. In order to do this, the maximum TA value may be set based on the minimum subcarrier interval of the frequency resource region (eg, a cell) constituting the TAG. For example, when different cell ranges are supported through different subcarrier intervals in the same site (e.g., when using the minimum subcarrier interval for a service supporting the maximum cell range, the minimum cell range). In the case of using the maximum subcarrier spacing for a service that supports a), the same TAG may be configured because it is the same area. In this case, it may be desirable to set the maximum TA value based on the minimum subcarrier interval in order to support a service supporting the maximum cell range with the same TA command.

In addition, when an uplink signal for inducing TA (ie, an uplink signal for generating TA adjustment) is explicitly defined, a TA command (i.e., based on a subcarrier interval of the CC (Component Carrier) transmitting the signal is defined. , TA command unit) and / or the maximum TA value may be determined.

For example, an uplink signal transmitted to allow a base station to determine a TA may be preset or defined. In a state in which the corresponding uplink signal (s) are set for each frequency resource region (eg, cell) or for each TAG, a TA command (ie, TA command) based on the set uplink signal or subcarrier interval of the actually transmitted uplink signal. Command unit) and maximum TA value can be determined. The method sets the TA command unit based on the maximum subcarrier interval among the plurality of subcarrier intervals constituting the corresponding TAG, and compares the method to determine the maximum TA value based on the minimum subcarrier interval. There is an advantage to optimize the size of. That is, there is an advantage in terms of reducing overhead of the TA command field.

In addition, a TA command (ie, a TA command unit) and / or a maximum TA value may be determined based on a subcarrier interval of a CC (Component Carrier) used when the base station transmits the (N) PDCCH order.

The RA procedure according to the (N) PDCCH order is an operation in the RRC connection configuration state, and is a method in which the base station instructs the RA procedure for a specific frequency resource region (eg, a cell) to a specific UE. Therefore, by setting the TA command unit and the maximum TA value based on the subcarrier interval of the corresponding frequency resource region (eg, cell), the TA command unit is set based on the maximum subcarrier interval and based on the minimum subcarrier interval. Compared to the method of determining the maximum TA value, there is an advantage that the size of the TA command field can be optimized. That is, there is an advantage in terms of reducing overhead of the TA command field.

In addition, in the present embodiment, when the initial TA command supports up to the radius of the maximum cell and uses a tracking TA command to support finer adjustment than the initial TA command, the initial TA command The bit field size of the control and tracking TA commands may be set differently, or the minimum adjustment unit may be set differently.

For example, in the case of the tracking TA command, the maximum adjustment range may be set smaller than that of the initial TA command, and the minimum adjustment unit may be set smaller than in the case of the initial TA command. Alternatively, for the above-described purposes, bit fields of the same size or different sizes may be set to be interpreted differently according to an initial TA command or a tracking TA command. Alternatively, for the purpose as described above, the information set by the base station may be broadcasted as system information or implicitly transmitted through a PRACH format configuration.

In addition, a TA adjustment unit (eg, Ts ″ or Tc ″) that the UE actually applies may be determined in the following manners.

First, Ts may be determined by a maximum bandwidth that can be set in a corresponding frequency band. Thereafter, the TA reference adjustment unit Ts '(or Tc') may be determined based on the determined Ts (or Tc). For example, Ts' may be expressed as k * Ts, where k may be determined based on motion or specific (reference) neurology (eg, specific subcarrier spacing, specific CP).

When Ts' is determined, the TA adjustment unit of the actual terminal may be determined according to the relationship with the operation or the specific (reference) neurology. In this case, the TA adjustment unit Ts' 'of the terminal may be expressed as m * Ts' (that is, m * k * Ts). Here, m may mean a reference subcarrier interval / terminal subcarrier interval when only the subcarrier interval is considered. For example, when the reference subcarrier interval is 15 kHz and the terminal subcarrier interval is 60 kHz, m may be 1/4.

Alternatively, when the numerology between frequency resource regions (eg, cells) constituting the TAG is different, the TA command may be configured by a combination of the neurology belonging to the TAG. For example, when the TA adjustment unit of the terminal having the first subcarrier interval is Ts_1 and the TA adjustment unit of the terminal having the second subcarrier interval is Ts_2, the TA command is in the form of a * Ts_1 + b * Ts_2. It may be configured.

Fourth embodiment

In this embodiment, a method of setting an activation or reactivation timing of an SCell in an NR system will be described.

In the CA operation in the NR system, all or part of one or more configured SCells that are not used by the terminal may be deactivated in order to reduce power of the terminal, and may be reactivated when the terminal is required. May be considered.

Upon activation or reactivation of the SCell, if the terminal receives an activation or deactivation indication (via the MAC-CE) from a base station in a specific subframe (for example, the nth subframe), the terminal may receive a corresponding SCell after a certain time therefrom. May be set to start the deactivation timer (ie, SCellDeactivationTimer) or restart it in case of reactivation. Here, the start point of the timer may be set in units of subframes or slots. In one example, the timer may be set to start or restart in the n + k3th subframe.

Specifically, when setting the start or restart timing of the SCell deactivation timer when referring to the lighting supporting the diversity and / or large value of the subcarrier interval in the NR system, the following methods 4-1) to 4-3) can be considered.

Here, the start or restart timing of the SCell deactivation timer may include SRS transmission timing, CSI reporting timing, PDCCH monitoring timing, and / or after SCell (re) activation. PHR (Power Headroom Report) triggering timing and the like.

Method 4-1)

First, the timing associated with activation or reactivation of the SCell may be set to an absolute time (eg, microseconds (us), etc.). In this case, the method can be applied equally for all neurology.

Method 4-2)

Next, timing associated with activation or reactivation of the SCell may be interpreted in association with the neurology of the cell (ie, the frequency resource region of the cell). In this case, the value of the timing may be scaled and interpreted according to the subcarrier spacing.

Method 4-3)

Next, a timing related to activation or reactivation of the SCell is determined by the base station, and the corresponding information may be broadcast through system information (eg, a system information block). That is, the base station may set a timing related to activation or reactivation of the SCell, and broadcast it through a system information block.

Fifth Embodiment

In the present embodiment, a method of determining a requirement for a timing difference in an NR system will be described.

When determining the cell radius and / or number of TAGs in a network in CA operation in an NR system, the cell radius is limited and the number of TAGs is limited in consideration of the buffer size of the receiver. Can be set to To this end, a requirement for a timing difference that can be tolerated by the UE needs to be set, and such a requirement can be considered when determining the cell radius and / or the number of TAGs.

In determining the requirements for the timing difference, the maximum receiver bandwidth and cyclic prefix (CP) that can be set in the corresponding frequency band need to be considered. Assuming that the same UE buffer size, the larger the reception bandwidth, the smaller the CP, the data throughput increases, so it is acceptable when control information is delayed in the downlink to the terminal. This is because the delay can be reduced. In addition, since the terminal buffer size is related to the UE capability, the number of TAGs supported by the terminal may be limited according to the terminal buffer size or the capability of the terminal.

In addition, in consideration of the burden of the receiver buffer size for the scheduled cell and / or HARQ latency for the scheduled cell, cross-carrier scheduling ) May also be considered.

For example, cross-CC scheduling between two Component Carriers (CCs) in which a TA difference exceeds 'X us' and / or a subcarrier difference exceeds 'Y times' may not be allowed. Specifically, the difference between the TA of the scheduling cell and the TA of the scheduled cell exceeds 'X us' and / or the subcarrier interval of the scheduling cell is greater than the subcarrier interval of the scheduled cell. Cross-CC scheduling between two CCs greater than or equal to 'Y times' may not be allowed.

9 is a flowchart illustrating an operation of a terminal for adjusting uplink timing in a wireless communication system to which the method proposed in the present specification can be applied. 9 is merely for convenience of description and does not limit the scope of the invention.

Referring to FIG. 9, it is assumed that a corresponding terminal supports carrier aggregation (CA) operation in an NR system, and it is assumed that the terminal operates based on the above-described embodiments of the present specification. For example, in FIG. 9, the terminal may be configured to adjust uplink timing (ie, uplink transmission timing) based on the TA command setting method described in the above-described third embodiment.

The UE may transmit an uplink signal (for example, the RA preamble, PUCCH, PUSCH, SRS, etc.) to the base station (step S905).

Thereafter, the terminal may receive a TA command set based on an uplink signal transmitted from the base station (S910). For example, the TA command may be set based on the above-described method (eg, the third embodiment).

Upon receiving the TA command, the terminal may perform uplink transmission by applying the TA indicated by the corresponding TA command (step S915).

In this case, the TA command may be interpreted according to a subcarrier spacing of at least one frequency resource region (for example, a frequency resource region corresponding to a cell) to which the TA is to be applied.

In addition, the terminal may further receive information on the TAG from the base station, this operation may be performed before receiving the TA command from the base station. In this case, the TA command received by the terminal may be a TA command corresponding to the TAG indicated by the base station.

When the uplink signal is the RA preamble, the TA command may be included in a RAR (ie, a RAR message) transmitted by the base station in response to the preamble.

Alternatively, if the corresponding TA is applied for updating an uplink timing previously set or indicated to the UE, the TA command may be included in the MAC-CE and received. In this case, it may be assumed that the terminal is in a state where a radio resource control connection (RRC connection) is established.

In addition, as described above, the TA command may be set based on a maximum subcarrier spacing among the subcarrier intervals of the frequency resource regions (eg, the frequency resource regions corresponding to the cell) constituting the TAG. have. In addition, the maximum TA value indicated by the TA command may be set based on a minimum subcarrier spacing among the subcarrier intervals of the frequency resource regions constituting the TAG. In addition, an offset between a timing of receiving a TA command and a timing of performing uplink transmission by applying the TA command may be set in a subframe or slot unit according to a subcarrier interval.

General apparatus to which the present invention can be applied

10 illustrates a block diagram of a wireless communication device according to an embodiment of the present invention.

Referring to FIG. 10, a wireless communication system includes a base station (or network) 1010 and a terminal 1020.

The base station 1010 includes a processor 1011, a memory 1012, and a communication module 1013.

The processor 1011 implements the functions, processes, and / or methods proposed in FIGS. 1 to 9. Layers of the wired / wireless interface protocol may be implemented by the processor 1011. The memory 1012 is connected to the processor 1011 and stores various information for driving the processor 1011. The communication module 1013 is connected to the processor 1011 and transmits and / or receives a wired / wireless signal.

The communication module 1013 may include a radio frequency unit (RF) unit for transmitting / receiving a radio signal.

The terminal 1020 includes a processor 1021, a memory 1022, and a communication module (or RF unit) 1023. The processor 1021 implements the functions, processes, and / or methods proposed in FIGS. 1 to 9. Layers of the air interface protocol may be implemented by the processor 1021. The memory 1022 is connected to the processor 1021 and stores various information for driving the processor 1021. The communication module 1023 is connected to the processor 1021 to transmit and / or receive a radio signal.

The memories 1012 and 1022 may be inside or outside the processors 1011 and 1021, and may be connected to the processors 1011 and 1021 by various well-known means.

In addition, the base station 1010 and / or the terminal 1020 may have a single antenna or multiple antennas.

11 is a block diagram illustrating a communication device according to one embodiment of the present invention.

In particular, FIG. 11 is a diagram illustrating the terminal of FIG. 10 in more detail.

Referring to FIG. 11, a terminal may include a processor (or a digital signal processor (DSP) 1110, an RF module (or an RF unit) 1135, and a power management module 1105). ), Antenna 1140, battery 1155, display 1115, keypad 1120, memory 1130, SIM card Subscriber Identification Module card) 1125 (this configuration is optional), a speaker 1145, and a microphone 1150. The terminal may also include a single antenna or multiple antennas. Can be.

The processor 1110 implements the functions, processes, and / or methods proposed in FIGS. 1 to 9. The layer of the air interface protocol may be implemented by the processor 1110.

The memory 1130 is connected to the processor 1110 and stores information related to the operation of the processor 1110. The memory 1130 may be inside or outside the processor 1110 and may be connected to the processor 1110 by various well-known means.

The user inputs command information such as a telephone number, for example, by pressing (or touching) a button on the keypad 1120 or by voice activation using the microphone 1150. The processor 1110 receives the command information, processes the telephone number, and performs a proper function. Operational data may be extracted from the SIM card 1125 or the memory 1130. In addition, the processor 1110 may display command information or driving information on the display 1115 for the user to recognize and for convenience.

The RF module 1135 is connected to the processor 1110 and transmits and / or receives an RF signal. The processor 1110 transmits command information to the RF module 1135 to transmit, for example, a radio signal constituting voice communication data to initiate communication. The RF module 1135 is composed of a receiver and a transmitter for receiving and transmitting a radio signal. The antenna 1140 functions to transmit and receive radio signals. Upon receiving the wireless signal, the RF module 1135 may forward the signal and convert the signal to baseband for processing by the processor 1110. The processed signal may be converted into audible or readable information output through the speaker 1145.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature is to be considered optional unless stated otherwise. Each component or feature may be embodied in a form that is not combined with other components or features. In addition, it is also possible to configure the embodiments of the present invention by combining some components and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation in the claims, or may be incorporated into new claims by post-application correction.

Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. For implementation in hardware, an embodiment of the present invention may include one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and FPGAs ( field programmable gate arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above. The software code may be stored in memory and driven by the processor. The memory may be located inside or outside the processor, and may exchange data with the processor by various known means.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the essential features of the present invention. Accordingly, the above detailed description should not be construed as limiting in all respects but should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention.

1010: base station 1020: terminal

Claims (12)

A method for receiving a uplink signal from a base station in a wireless communication system,
Receiving a first uplink signal from a terminal;
Transmitting a first TA command (Timing Advance command) set based on the first uplink signal to the terminal;
Receiving a second uplink signal from the terminal;
A Timing Advance (TA) value based on the first TA command is applied to the second uplink signal; And
And transmitting a second TA command for updating the TA value to the terminal.
The first TA command and the second TA command are set based on a maximum subcarrier spacing among subcarrier spacings of a plurality of frequency regions for the terminal.
And a maximum value of the TA value is set based on a minimum subcarrier interval of the subcarrier intervals. The method of claim 1,
And wherein the plurality of frequency domains are included in the same timing advertisement group (TAG). The method of claim 2,
The first uplink signal is a preamble for random access to the base station,
The first TA command is included in a random access response that the base station transmits in response to the preamble. The method of claim 1,
The second TA command is included in the Medium Access Control-Control Element (MAC-CE) and transmitted. The method of claim 4, wherein
The terminal has a radio resource control connection (Radio Resource Control connection) is set,
The second uplink signal is at least one of a physical uplink control channel, a physical uplink shared channel, or a sounding reference signal. Way. The method of claim 4, wherein
The bit field size or the minimum adjustment unit of the first TA command and the second TA command are set differently. The method of claim 2,
The field size for the TA value is set based on the minimum subcarrier spacing. The method of claim 2,
The offset between the reception timing of the first TA command and the transmission timing of the second uplink signal is set in slot units according to the subcarrier spacing. A base station for transmitting an uplink signal in a wireless communication system,
An RF module for transmitting and receiving a radio signal; And
A processor functionally connected with the RF module,
The processor,
Control the RF module to receive a first uplink signal from a terminal;
Controlling the RF module to transmit a first TA command to a user equipment based on the first uplink signal;
The RF module is controlled to receive a second uplink signal from the terminal.
A Timing Advance (TA) value based on the first TA command is applied to the second uplink signal; And
The RF module is controlled to transmit a second TA command for updating the TA value to the terminal.
The first TA command and the second TA command are set based on a maximum subcarrier spacing among subcarrier spacings of a plurality of frequency regions for the terminal.
And a maximum value of the TA value is set based on a minimum subcarrier interval of the subcarrier intervals. The method of claim 9,
And the plurality of frequency domains are included in the same timing advertisement group (TAG). The method of claim 10,
The first uplink signal is a preamble for random access to the base station,
The first TA command is included in a random access response transmitted by the base station in response to the preamble. The method of claim 9,
The second TA command is received in a medium access control-control element (MAC-CE).

Images